CAREER: Isolated Piezoelectric Transformers for Miniaturized Power Conversion

About This Grant

Power electronics convert and control the electrical energy we use every day, and their advancement is critical to renewable energy, electric transportation, manufacturing, consumer electronics, computing, healthcare, and more. Next-generation technologies demand power electronics with ever-increasing efficiency and performance with ever-decreasing size and cost, but advancement along these dimensions is majorly bottlenecked by the passive components (i.e., energy storage elements) integral to their operation. This work will elucidate how an alternative passive component technology – isolated piezoelectric transformers – could enable major advances in the miniaturization and performance of power electronics. Piezoelectric components offer very high theoretical efficiencies and energy densities with favorable scalability to small sizes, but so far these advantages have only been realized in a narrow range of power conversion applications. Isolated piezoelectric transformers are positioned to extend the advantages of piezoelectrics to a wide variety of applications that require electrical isolation, such as grid-connected power supplies and medical devices, removing their need for bulky, lossy magnetic transformers. This project will generate significantly expanded scientific knowledge of piezoelectric materials and components as power passive components, and how to best utilize them in power electronics to enable drastic miniaturization and performance improvements. Further, the proposed educational activities will lay a foundation for realizing an expanded and interdisciplinary workforce in power electronics, electrical engineering, and STEM. While piezoelectric resonators have achieved promising efficiencies and power handling densities as power passive components, piezoelectric transformers have been limited to an order of magnitude greater loss and two orders of magnitude lower power density. This highlights a significant gap in demonstrated performance between components of comparable theoretical capability, so there is an opportunity to apply what is now understood about designing piezoelectric resonators to the development of high-efficiency, high-power-density isolated piezoelectric transformers. To pursue this on multiple levels, the research objectives of this project will include (1) characterizing and modeling piezoelectric material losses, (2) designing high-efficiency, high-power-density isolated piezoelectric transformers, and (3) developing power converter circuit topologies and control strategies that best utilize isolated piezoelectric transformers. The resulting models and design techniques will be validated in multiple experimental demonstrations of isolated piezoelectric-transformer-based power converters. The education objectives of this project include (1) developing a hands-on, open-access power electronics curriculum, (2) broadening participation in power electronics and STEM through curriculum intervention and other means, and (3) bridging the expertise gap between power electronics and acoustics/MEMS through professional education. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.